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A Practical Guide To Management of Hyperlipidaemia

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Hyperlipidaemia: Definition

Hyperlipidaemia is a condition characterised by increased concentrations of lipids (triglycerides, cholesterol) and lipoproteins [low density lipoproteins (LDL) and very low density lipoproteins (VLDL)] in the blood.
Clinical presentation
  • Hypercholesterolaemia: Increased cholesterol levels
  • Hypertriglyceridaemia: Increased triglyceride levels
  • Mixed hyperlipidaemia: Increased cholesterol and triglyceride levels
    •

 

Classification of hyperlipidaemia
  • Primary hyperlipidaemia: This occurs as a result of a genetic defect.
  • Secondary hyperlipidaemia: This occurs as a result of another illness or metabolic disturbance e.g. diabetes mellitus.

 

Hyperlipidaemia: Predisposing factors
  • Age (males > 45 years, females > 55 years)
  • Heredity
  • Sedentary life style
  • Diet rich in saturated fats and cholesterol
  • Associated medical conditions e.g. diabetes mellitus, nephrotic syndrome, hypothyroidism, alcoholism, obstructive liver disease, etc.

 

Consequence of hyperlipidaemia
  • Hyperlipidaemia is a major risk factor for atherosclerosis. Atherosclerosis is the underlying disorder in a vast majority of cases of coronary heart disease (angina, myocardial infarction). It is also a major risk factor for stroke.

Figure : Process of atherosclerosis

hyp1.gif (4712 bytes) hyp2.gif (4798 bytes) hyp3.gif (4729 bytes) hyp4.gif (4795 bytes)
Blood flows smoothly Plaque begins to develop. Blood flow slows down. Plaque development progresses. Blood flow partially blocked.

 

Plaque ruptures leading to clot formation. Blood flow blocked.
  • Low density lipoprotein (LDL) is pro-atherogenic. Hence high levels of LDL increase coronary heart disease (CHD) risk.
  • High density lipoprotein (HDL) is anti-atherogenic. Hence low levels of HDL increase CHD risk.

Every 1% increase in cholesterol leads to a 2% increase in CHD risk.


Diagnosis of hyperlipidaemia
  • Serum cholesterol estimation
    The United States National Cholesterol Education Program (NCEP) guidelines state that serum total cholesterol and HDL-cholesterol should be measured in all adults 20 years of age and over, at least once every 5 years.

    In individuals who do not have CHD (no previous history of angina, myocardial infarction), the total cholesterol and HDL-cholesterol should be first measured. Then depending on the values and the risk factors for CHD present in that particular patient, LDL-cholesterol should be measured.
Total Cholesterol
<200 mg/dl Desirable
200-239 mg/dl Borderline-High
>240 mg/dl High
HDL Cholesterol
<35 mg/dl Low
  • Lipoprotein analysis (for estimation of LDL cholesterol)
    This includes measurement of fasting (12-14 hours) levels of total cholesterol, total triglycerides and HDL-cholesterol. From these values, the LDL-cholesterol value is estimated.

Lipoprotein analysis is required for the following patients:

  • Person with blood cholesterol <200 mg/dl and HDL-cholesterol < 35 mg/dl
  • Person with total cholesterol levels of 200 to 239 mg/dl who have an HDL- cholesterol less than 35 mg/dl or two or more risk factors for CHD
  • Person whose total cholesterol is 240 mg/dl or greater
  • All patients of CHD

Alternatively, a lipoprotein analysis may be performed for all patients.
CHD Risk Factors
Positive
  • Age : Male >45 years
             Female > 55 years or premature menopause without estrogen replacement          therapy
  • Family history of premature CHD
  • Smoking
  • Hypertension
  • HDL-cholesterol <35 mg/dl
  • Diabetes
Negative
  • HDL-cholesterol >60 mg/dl

When to initiate lipid-lowering therapy

The decision to treat hyperlipidaemia with dietary therapy or drugs is based on the LDL-cholesterol value. The aim is to achieve the appropriate LDL goal.
Patient Profile LDL goal
Without CHD and with fewer than 2 risk factors <160 mg/dl
Without CHD and with 2 or more risk factors <130 mg/dl
With CHD <100 mg/dl

Thus, as shown in the table, for a patient without CHD and with less than two risk factors for CHD, therapy should be initiated if his LDL level is
>160 mg/dl. In a patient without CHD and with 2 or more risk factors, therapy should be initiated if his LDL is >130 mg/dl. For a patient with CHD, therapy should be initiated if his LDL is >100 mg/dl.
Dietary therapy and other life style modifications
  • Reduce intake of foods rich in saturated fats and cholesterol.
Examples of foods rich in saturated fats Examples of foods rich in cholesterol
Beef, pork, butter, whole milk, eggs, cheese, ghee, coconut oil, palm oil, vanaspati, margarine Eggs, dairy products, beef, pork, organ meats like liver, heart etc.
  • Increase intake of soluble fiber. Soluble fiber is present in all fruits and vegetables. Whole pulses like moong, chawli, beans and peas are also very good sources of soluble fiber.
  • If cholesterol levels are not controlled with dietary therapy, consideration should be given to using drugs. Drug therapy should be added to dietary therapy and not substituted for it.
  • Reduce weight.
  • Exercise regularly.
  • Stop smoking.
  • Reduce alcohol intake.
  • Control other conditions like hypertension, diabetes mellitus, etc.

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